So, the most common reasons to do a engine rebuild are loss of compression; excessive oil consumption; engine knocking noise and excessive oil clearances.
Engine Rebuild – Is It Worth It ? This may not be a easy question to answer.
The symptoms of loss of compression are; extended cranking (hard to start), lack of power, or a misfire (running rough).
All of these symptoms can be caused by lack of compression, but they can also be caused by other things. So, before doing a engine rebuild it should be diagnosed; by performing a compression or leak down test.
Oil consumption is the loss of motor oil; even though there are no significant external oil leaks.
Oil consumption can be caused by:
- Worn valve guides.
- Dried valve guide seals.
- Stuck oil control rings.
- Excessive cylinder to piston clearance.
The most common symptom of excessive oil clearances is; an awful knock coming from the engine. Low oil pressure is also a symptom of excessive oil clearances. But, is less common (by the time the oil pressure goes low there’s usually an engine knock evident).
Is It Worth It, To Repair Or Rebuild My Engine ?
Most of the time it comes down to a personal choice. There is no good formulaic solution to the question. There are cases where it’s an easy decision. If the car is 20 years old with 300,000 miles on it and is falling apart at the seams; then it’s pretty obvious it makes no sense to fix it. If the car is 5 years old and in good shape it’s definitely worth fixing. Most of the cars that need engines fall somewhere in-between.
Consider the total projected cost of the engine; plus any needed maintenance and repairs. Consider whether you like your car or not and; the cost of buying a new or used car you would like. Keep in mind that there is some uncertainty in buying a used car; even if you have it inspected. Remember to include financing costs and full coverage insurance when thinking about a new car. In some cases it is worth doing repairs to a car in excess of its blue book value.
So, If I Do A Engine Rebuild, My Car Will Be Like New, Right ?
No: The car is much more than just the engine. There’s steering, suspension, transmission, brakes, tires, axles, fuel injection, smog equipment, and a lot more. A car with a rebuilt engine will still run poorly with bad ignition wires; and still fail smog with a bad O2 sensor; and still overheat with a bad radiator.
How Do I Break In A Rebuilt Engine ?
Vary the engine speed and load. Don’t use over 75% throttle. Never go over 75% of the maximum (RPM). Don’t use synthetic oil. Never let the engine idle for extended periods. Don’t cruise on the freeway at the same speed for extended periods. It should only take about 500 miles to break an engine in. After that change the oil and do what you want. Believe it or not, how you break your engine in can make a huge difference; in how long your rebuilt engine lasts and how much oil it uses. You should also be aware that the rebuilt engine; will burn more oil as it is breaking in, so check the oil frequently.
So, why did the engine fail in the first place ? This is important to consider. If your maintenance was spotty and you don’t change your habits; then the new engine will fail as well. Finally, there usually is a correctable reason for engine failure.
Thank You !